Visible light belongs to the wavelengths between 380nm to 750nm. Wavelengths lower than 380nm are called ultra-violet (UV) wavelengths and contain high amounts of energy that can be harmful to plants. Only about 5of sunlight is in the UV range, and greenhouse coverings tend to reduce that fraction further. It should be noted, that some artificial light sources generate UV, except the LED grow light
Photosynthesis is driven by wavelengths in the range of 400nm to 700nm, where roughly 50of solar radiation occurs. Below this range, photosynthetic pigments poorly absorb light, and at the higher wavelengths, the energy is insufficient to support the requirements of photosynthesis. Plants utilize the light from LED grow light environment as an important developmental cue. Plants use their pigments, mainly by phytochrome to detect receiving light. Phytochrome participates in many aspects of plant development, including the regulation of stem elongation, leaf enlargement, and sometimes flowering.
Leaves absorb wavelengths effectively up to just above 700nm, mainly due to photosynthetic pigments, but do not absorb well in the 700nm to 860nm ranges.(PS. LED grow light can emit full spectrum for all phase of plant growth). In addition to plant pigments, water within plant tissues absorb infra-red (IR) region of receiving light. Only a small fraction of the absorbed energy from light is dissipated by plant metabolism. The great majority is dissipated by evapotranspiration, convective heat loss, and long-wavelength re-radiation (>3000nm).
LED grow light is the most efficient type of grow lighting that can be purchased. Compare to HID or fluorescent grow light, LED grow light can save 70-80electricity bill and don\’t contain any harmful substance for environment friendly.